| 摘要 |
PURPOSE:To obtain a powdery copolymer having easy handleability free from tackiness in high yield, by copolymerizing a mixture of N-vinylformamide and acrylonitrile in the amount ratio in a specific range in an aqueous medium at a specific monomer concentration. CONSTITUTION:A mixture of N-vinylformamide and acrylonitrile in the molar ratio of 5:95-55:45, preferably 35:60-50:50 is copolymerized in an aqueous medium under the condition of 5-25wt.% monomer concentration by using 0.01-1wt.% based on the monomers of a radical polymerization initiator such as usually 2,2' azobis-2-amidinopropane hydrochloride preferably in an inert gas flow at 30-100 deg.C and a formed polymer is obtained in a precipitate state. When the prepared water-insoluble copolymer is hydrolyzed and modified, a water-soluble or hydrophilic copolymer having high value as flocculant or additive for paper manufacturing is efficiently obtained. |
